zoj 1530 Find The Multiple
Given a positive integer n, write a program to find out a nonzero multiple m of n whose decimal representation contains only the digits 0 and 1. You may assume that n is not greater than 200 and there is a corresponding m containing no more than 100 decimal digits.
Input
The input file may contain multiple test cases. Each line contains a value of n (1 <= n <= 200). A line containing a zero (0) terminates the input.
Output
For each value of n in the input print a line containing the corresponding value of m. The decimal representation of m must not contain more than 100 digits. If there are multiple solutions for a given value of n, any one of them is acceptable.
Sample Input
2
6
19
0
Sample Output
10
100100100100100100
111111111111111111
Source: Asia 2002, Dhaka (Bengal)
題意:給你一個數n,讓你找n的倍數m,m的十進制中只能有1和0,問最小的m是幾。
思路:若沒有是n的倍數的條件,如何構造01序列?開一個隊列,先把1放進去。然後取出1,把1*10,1*10+1放進去,以此類推是n的倍數只需要判斷一下即可,但答案可能爆long logn,所以用同余定理 若a%b=c,那麽ax%b=cx%b (x!=0),用字符數組記錄01序列,同時記錄這個01序列%n的余數。還有一個問題,空間消耗巨大,
#include<queue> #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> using namespace std; struct nond{ string s; int mod; }cur,net; int n; bool vis[1000001]; int main(){ while(1){ queue<nond>que; memset(vis,0,sizeof(vis)); scanf("%d",&n); if(n==0) break; cur.s="1";cur.mod=1; que.push(cur); while(!que.empty()){ cur=que.front(); que.pop(); net.mod=(cur.mod*10)%n; net.s=cur.s+‘0‘; if(net.mod==0){ cout<<net.s<<endl; break; } if(!vis[net.mod]){ que.push(net); vis[net.mod]=1; } net.mod=(cur.mod*10+1)%n; net.s=cur.s+‘1‘; if(net.mod==0){ cout<<net.s<<endl; break; } if(!vis[net.mod]){ que.push(net); vis[net.mod]=1; } } } }
zoj 1530 Find The Multiple